Nonlocal Behavior Research Articles

Nonlinear thermo-mechanical stress-driven modeling of nano arches augmented by higher order double-scaled kernel

Modeling the nonlocal behavior of small-scale structures is almost controversial. The recently developed approach, known as the stress-driven nonlocal model, in which the stress is the input of nonlocal integral, has been proved to pose as a remedy for the ill-posing behavior of strain-driven solutions. Though it is still in its early stages, stress-driven modeling of the nonlinear behavior of nano-scaled problems needs further thought. The coupled displacement field, in particular, makes nano-arches more challenging. The stress-driven formulation, enhanced by constitutive boundary conditions, reveals the thermo-mechanical buckling and post-buckling features of shallow nano-arches for the first time in this research. Furthermore, the single-scaled Helmholtz kernel is replaced with the more appropriate double-scaled kernel known as the bi-Helmholtz averaging nonlocal kernel. Higher-order continuity of the bi-Helmholtz kernel and, hence, constitutive boundary conditions and higher-order differential equations corresponding to the stress-driven scheme hold the key to efficiency. The arch is subjected to uniform temperature and radial pressure at the same time. To demonstrate the response of the nano-arch during buckling and post-buckling, the nonlinear equilibrium path, whether for mechanical or thermal loading, is given for the first time by prevailing on the challenges of the higher-order problems. Moreover, it would be beneficial if one could have the chance to recognize how and when the arch buckles. These valuable data are available in this study to give the limiting parameters at the moment of buckling, including limiting temperature, nonlocal parameter, and geometry.

An accelerated novel meshless coupled algorithm for Non-local nonlinear behavior in 2D/3D space-fractional GPEs

In this work, an accelerated novel meshless coupled algorithm is first presented for the numerical study of high-dimensional space-fractional nonlinear Schrödinger or Gross-Pitaevskii equations (SFNLS/GPEs). The proposed meshless method is motivated by the novel coupled concepts: (a) a time splitting-step is adopted to decompose the NLSE; (b) the spatial Riesz fractional derivative under the Riemann-Liouville operator is discretized by the combination of numerical integration and meshless weighted-least-square schemes; (c) an accurate absorbing boundary condition is employed to treat the unbounded domain. Meanwhile, a parallel algorithm based on the above approximated schemes is designed to reduce the computing cost on a CUDA-program-based GPU card. Subsequently, the validation and numerical convergence rate of the proposed method for SFNLSE are discussed and illustrated by solving two 2D/3D examples. Furthermore, the proposed parallel meshless algorithm is extended to predict the nonlinear dynamic behaviors dominated by the space-fractional Gross-Pitaevskii equations (SFGPEs), and the influence of nonlocal effect on the nonlinear phenomena is also discussed. The presented numerical results illustrate that the proposed algorithm for multi-dimensional SFNLSEs is reliability and high-efficient.

Modeling Long-Distance Forward and Backward Diffusion Processes in Tracer Transport Using the Fractional Laplacian on Bounded Domains

Recent studies have emphasized the importance of the long-distance diffusion model in characterizing tracer transport occurring within both subsurface and surface environments, particularly in heterogeneous systems. Long-distance diffusion, often referred to as nonlocal diffusion, signifies that tracer particles may experience a considerably long distance in either the forward or backward direction along preferential channels during the transport. The classical advection–diffusion (ADE) model has been widely used to describe tracer transport; however, they often fall short in capturing the intricacies of nonlocal diffusion processes. The fractional operator has gained recognition among hydrologists due to its potential to capture distinct mechanisms of transport and storage for tracer particles exhibiting nonlocal dynamics. However, the hypersingularity of the fractional Laplacian operator presents considerable difficulties in its numerical approximation in bounded domains. This study focuses on the development and application of the fractional Laplacian-based model to characterize nonlocal tracer transport behavior, specifically considering both forward and backward diffusion processes on bounded domains. The Riesz fractional Laplacian provides a mathematical framework for describing tracer diffusion processes on a bounded domain, and a novel finite difference method (FDM) is introduced as an effective numerical solver for addressing the fractional Laplacian-based model. Applications reveal that the fractional Laplacian-based model can effectively capture the observed nonlocal tracer transport behavior in a heterogeneous system, and nonlocal tracer transport exhibits dynamic characteristics, influenced by the evolving heterogeneity of the media at various temporal scales.

Effects of global warming, time delay and chaos control on the dynamics of a chaotic atmospheric propagation model within the frame of Caputo fractional operator

The Lorenz-84 climate model is a simplified mathematical model that describes the chaotic behavior of atmospheric convection and its impact on global climate patterns. It captures the presence of chaotic behavior in the motion of westerly wind and helps understand the concept of sensitivity to initial conditions. But as observed over the years, the westerlies are gaining more strength due to the rise in atmospheric temperature. In this work, we have modified the old model to observe the changes in the behavior of the system due to global warming and time delay. The modified model has been generalized using Caputo fractional derivative to provide a more accurate representation of the system with memory effect and non-local behavior. The stability of the new model has been tested at all the equilibrium points. Using Picard’s operator and Banach’s Fixed Point theorem, it has been shown that there exists a unique and bounded solution for the new model. It has been observed that the sole effect of global warming makes the system gradually unstable from chaotic as the fractional order α is decreased from 0.80 to 0.50. Also, a shift in the bifurcation point has been noticed for the new model. All three Lyapunov exponents have been calculated for different fractional orders to confirm the presence of chaos in the modified model as well. A chaos control law has been constructed for the modified chaotic model using the sliding mode control theory. Interestingly, the chaos disappears completely when the effect of time-delay is considered in the modified model. Since our proposed time-delayed modified model shows an asymptotically stable nature for all fractional orders α less than 0.85, it is better suited to make more accurate predictions about the strength of the westerlies.

Form-finding of elastic gridshell based on spatial elastica model

In engineering design, elastic gridshells, which are composed of a number of elastic rods, are advantageous because they are lightweight, easy to construct, and low-cost as well as have a long-span space. However, the form-finding of a gridshell is challenging owing to the large deformation and strong geometric-nonlinearity of the structure.In this paper, a new form-finding method based on spatial elastica model (FMSE) is proposed. The deformations of elastic rods, obtained via the elliptic integral solution of spatial elastica, is integrated into the overall deformation of the gridshell. A set of transcendental equations is solved using the quasi-Newton method to ensure that the deformation of the gridshell satisfies the given boundary conditions. To validate the proposed FMSE method, desktop experiments (designed using the theory of Chebyshev nets) are performed on gridshells made of glass fiber reinforced polymer rods. The predictions of the FMSE method agree well with the experimental results.Accordingly, the proposed FMSE method is expected to have potential applications in elastic gridshells, on the investigations of form-finding, load-bearing capability, non-local deformation behavior, and also stability of structures.

Nonlocal Static and Dynamical Vacuum Field Correlations and Casimir-Polder Interactions.

In this review, we investigate several aspects and features of spatial field correlations for the massless scalar field and the electromagnetic field, both in stationary and nonstationary conditions, and show how they manifest in two- and many-body static and dynamic dispersion interactions (van der Waals and Casimir-Polder). We initially analyze the spatial field correlations for noninteracting fields, stressing their nonlocal behavior, and their relation to two-body dispersion interactions. We then consider how field correlations are modified by the presence of a field source, such as an atom or in general a polarizable body, firstly in a stationary condition and then in a dynamical condition, starting from a nonstationary state. We first evaluate the spatial field correlation for the electric field in the stationary case, in the presence of a ground-state or excited-state atom, and then we consider its time evolution in the case of an initially nonstationary state. We discuss in detail their nonlocal features, in both stationary and nonstationary conditions. We then explicitly show how the nonlocality of field correlations can manifest itself in van der Waals and Casimir-Polder interactions between atoms, both in static and dynamic situations. We discuss how this can allow us to indirectly probe the existence and the properties of nonlocal vacuum field correlations of the electromagnetic field, a research subject of strong actual interest, also in consequence of recent measurements of spatial field correlations exploiting electro-optical sampling techniques. The subtle and intriguing relation between nonlocality and causality is also discussed.

The effect of nonlocal interaction on chaotic dynamics, Turing patterns, and population invasion in a prey-predator model.

Pattern formation is a central process that helps to understand the individuals' organizations according to different environmental conditions. This paper investigates a nonlocal spatiotemporal behavior of a prey-predator model with the Allee effect in the prey population and hunting cooperation in the predator population. The nonlocal interaction is considered in the intra-specific prey competition, and we find the analytical conditions for Turing and Hopf bifurcations for local and nonlocal models and the spatial-Hopf bifurcation for the nonlocal model. Different comparisons have been made between the local and nonlocal models through extensive numerical investigation to study the impact of nonlocal interaction. In particular, a legitimate range of nonlocal interaction coefficients causes the occurrence of spatial-Hopf bifurcation, which is the emergence of periodic patterns in both time and space from homogeneous periodic solutions. With an increase in the range of nonlocal interaction, the whole Turing pattern suppresses after a certain threshold, and no pure Turing pattern exists for such cases. Specifically, at low diffusion rates for the predators, nonlocal interaction in the prey population leads to the extinction of predators. As the diffusion rate of predators increases, impulsive wave solutions emerge in both prey and predator populations in a one-dimensional spatial domain. This study also includes the effect of nonlocal interaction on the invasion of populations in a two-dimensional spatial domain, and the nonlocal model produces a patchy structure behind the invasion where the local model predicts only the homogeneous structure for such cases.

Visualizing the Hardy's Paradox using Hyper‐Entanglement‐Assisted Ghost Imaging

AbstractThe concept of quantum nonlocality, lying at the heart of quantum information science and technologies, is physically counter‐intuitive and mathematically elusive. Here, a hyper‐entanglement‐assisted ghost imaging system is designed to visualize the evidence of Hardy's paradox by capturing the purely nonlocal photonic events with a spatially resolved intensified charge‐coupled device (ICCD) camera. In the two‐photon polarization‐spatial‐mode hyper‐entangled state, spatial entanglement conveys the ghost images while polarization entanglement encodes the imaging channels in the logical structure of Hardy's nonlocality proof. Then whether the single ghost image of a skull‐shape object is observed or not can be a direct yet intuitive signature to support or defy quantum mechanics. Moreover, the degree of the violation of locality can be characterized by the contrast‐to‐noise ratio of ghost images macroscopically, and the nonlocal behavior of violating the locality microscopically at the single‐pixel level with a reasonable confidence level of 75% is also achieved. The proposed strategy not only sheds new light on the fundamental issue of quantum mechanics, but also holds promise for developing hyper‐entanglement‐based quantum imaging technology.

On the Solitary Waves and Nonlinear Oscillations to the Fractional Schrödinger–KdV Equation in the Framework of the Caputo Operator

The fractional Schrödinger–Korteweg-de Vries (S-KdV) equation is an important mathematical model that incorporates the nonlinear dynamics of the KdV equation with the quantum mechanical effects described by the Schrödinger equation. Motivated by the several applications of the mentioned evolution equation, in this investigation, the Laplace residual power series method (LRPSM) is employed to analyze the fractional S-KdV equation in the framework of the Caputo operator. By incorporating both the Caputo operator and fractional derivatives into the mentioned evolution equation, we can account for memory effects and non-local behavior. The LRPSM is a powerful analytical technique for the solution of fractional differential equations and therefore it is adapted in our current study. In this study, we prove that the combination of the residual power series expansion with the Laplace transform yields precise and efficient solutions. Moreover, we investigate the behavior and properties of the (un)symmetric solutions to the fractional S-KdV equation using extensive numerical simulations and by considering various fractional orders and initial fractional values. The results contribute to the greater comprehension of the interplay between quantum mechanics and nonlinear dynamics in fractional systems and shed light on wave phenomena and symmetry soliton solutions in such equations. In addition, the proposed method successfully solves fractional differential equations with the Caputo operator, providing a valuable computational instrument for the analysis of complex physical systems. Moreover, the obtained results can describe many of the mysteries associated with the mechanism of nonlinear wave propagation in plasma physics.

Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields

Importance of studying Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields lies in its relevance to fundamental physical phenomena, its applications in various fields of science and engineering and its potential for technological advancements. The study of Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields, along with additional factors such as Joule heating, fractional derivatives and convection, represents a multifaceted and challenging problem in fluid dynamics and applied mathematics. In this study, we explore the combined effects of Joule heating due to electric current passing through the fluid and fractional derivatives that describe nonlocal behaviors. The fractional formulation leads to a relaxation mechanism that exhibits delay and recollection of the fluid motion. The organization of direct temperature and concentration changes in MHD flow is made possible by this formalization. A finite difference/finite element method is used to calculate the flow dynamics issue and fractionally linked fields. The physical factors explain how the topic under examination is relevant.

A nonlocal method to compute effective properties of viscoelastic composite materials based on peridynamic computational homogenization theory

This article presents a computational homogenization framework for viscoelastic composites within the framework of non-ordinary state-based peridynamic theory. The motivation to develop this framework stems from the desire to develop a homogenization scheme that can model processes and phenomena that are driven by nonlocal behaviour such as size effect and fracture for which frameworks based on the classical continuum theory lack the capability of modelling. The proposed framework was used to calculate the effective properties in both time and frequency domains of two viscoelastic matrix-inclusion composite systems, one with an elastic inclusion and viscoelastic matrix, and the other with viscoelastic inclusion and matrix. The results of calculations were found to compare well with results from the literature. A parametric study was also conducted to investigate the influence of nonlocal interaction on the effective properties by varying the horizon size. Results showed that increasing the degree of nonlocality reduces the stiffness of the composite system as well as increase its rate of creep. The capability to account for nonlocal interaction highlights the potential of this proposed scheme to provide a more comprehensive understanding of the behaviour of viscoelastic composite materials over a wide range of material behaviour.

Giant nonlocal edge conduction in the axion insulator state of MnBi2Te4

The recently discovered antiferromagnetic (AFM) topological insulator (TI) MnBi2Te4 represents a versatile material platform for exploring exotic topological quantum phenomena in nanoscale devices. It has been proposed that even-septuple-layer (even-SL) MnBi2Te4 can host helical hinge currents with unique nonlocal behavior, but experimental confirmation is still lacking. In this work, we report transport studies of exfoliated MnBi2Te4 flakes with varied thicknesses down to the few-nanometer regime. We observe giant nonlocal transport signals in even-SL devices when the system is in the axion insulator state but vanishingly small nonlocal signal in the odd-SL devices at the same magnetic field range. In conjunction with theoretical calculations, we demonstrate that the nonlocal transport is via the helical edge currents mainly distributed at the hinges between the side and top/bottom surfaces. The helical edge currents in the axion insulator state may find unique applications in topological quantum devices.

Study of turbulent transport in magnetized plasmas with flow using symplectic maps

Turbulent transport in a magnetized plasma of the kind found in tokamaks is modeled by a 2D wave spectrum that allows reduction to a symplectic map. The properties of particle transport when chaos sets in are analyzed in various circumstances including finite Larmor radius (FLR) effects and a background plasma flow. For large wave amplitudes, regular particle orbits become chaotic, which represents a type of Lagrangian turbulence. When chaos becomes global, it leads to the loss of particle confinement. Poloidal flows tend to decrease the chaos in some regions, and they can give rise to the formation of transport barriers. FLR effects not only reduce chaos but also give rise to non-local behavior. Thus, when the particles have a thermal distribution of Larmor radii, a non-Gaussian particle distribution function in space is obtained. However, the transport preserves its diffusive scaling when there is no flow. Previous results about the dependence of the diffusion coefficient with amplitude are re-derived analytically and numerically taking into account FLR effects. In the presence of general poloidal flows, the transport has to be described by a two-step map. They modify the nature of transport in the direction of the flow from diffusive to ballistic to super-ballistic, depending on the type of flow. The transverse transport, in turn, shows suppression of the oscillations with wave amplitude that are present in the absence of flow. When the plasma flow varies linearly with radius, the transport can be studied with a similar single-step map, and the transverse diffusion coefficient is reduced while parallel transport can become super-ballistic. For non-monotonic flows, there are accelerating modes that can produce ballistic-like particles while the bulk of the particles behaves diffusively.

Quantifying nonlocal bedload transport: A regional-based nonlocal model for bedload transport from local to global scales

Recent studies have emphasized the importance of nonlocal models in characterizing bedload transport in natural rivers, particularly in mixed-size gravel beds or steep hillslopes. Nonlocality denotes that a quantity (flux) at a specific location x is dependent on the conditions in the surrounding area, as opposed to solely at the location itself. This concept applies in bedload transport even in planar flumes, where particles are entrained at an upstream position and travel a finite distance, ultimately contributing nonlocally to the sediment flux. However, existing bedload transport models, such as the advection–diffusion equation (ADE) or the fractional derivative equation (FDE) models, are inadequate in characterizing the nonlocal transport behavior of bedload at a regional scale. Large errors may arise from the lack of an accurate description of the nonlocal bedload transport processes at regional scales. This study proposes a regional-based nonlocal bedload transport model, which is conceptualized from the probabilistic Exner-based equations and the peridynamic (PD) differential operator. The PD model encapsulates the nonlocal motion of bedload sediments on the basis of the PD differential operator, by utilizing a pre-defined weight function and influence domain. Comparisons demonstrate that the PD model serves as a generalized tool connecting the local and the global models with different PD functions and influence domains. Its variability on kernel function and influence domain, enable it conveniently describe sub-, super-, and normal diffusion behaviors of bedload transport.

Isotopic sourcing reveals changing subsistence, cultural diversity and biological correlates with palaeodiet in fourth- to seventh-century AD Bavaria

Stable carbon and nitrogen isotopic ratios (δ13C, δ15N) in bone collagen of archaeological skeletal finds are indicators of the protein sources in individuals’ basic diet. Isotopic sourcing allows us to quantify the biomass contribution of major dietary components and to differentiate between the source contribution of various animal species (domesticates, game). We re-evaluated previously published isotopic signatures in skeletons from three burial sites in Bavaria, dated from Late Antiquity to Early Mediaeval times (Erding-Klettham, Erding-Altenerding, Straubing-Bajuwarenstraße) by use of a mixing model. The result is a more detailed reconstruction, supported by contextual evidence, of both early subsistence economies and individual dietary preferences. We were able to confirm relationships between non-local dietary behaviour and foreign cultural influences (grave goods and artificial cranial modification) that have previously been suggested by the burial context and DNA analyses and that are plausibly explained by migration events. Moreover, we differentiated early and late immigrants from each other, requiring a re-evaluation of the earlier interpretation of exogamy. In addition, individual dietary preferences indicate even more migration events and social stratifications that could not previously be identified by the archaeological evidence alone.

Modelling of viscoelastic materials using non-ordinary state-based peridynamics

This paper proposes a framework for implementing viscoelastic constitutive model from the classical continuum mechanics (CCM) theory within non-ordinary state-based peridynamics (NOSBPD). The motivation stems from the inadequacy of CCM to model very complex material behaviours such as initiation and propagation of cracks and nonlocal behaviour due to size effects. The proposed formulation leverages on the constitutive correspondence between NOSBPD and CCM to incorporate a CCM viscoelastic constitutive model based on hereditary integral into NOSBPD. The combination of hereditary constitutive model and NOSBPD effectively makes this formulation a nonlocal time–space viscoelastic framework where temporal nonlocality is incorporated by a hereditary viscoelastic model which stipulates that the behaviour of a material at any point in time depends on both the present action and the complete history of previous actions on the material, and spatial nonlocality on the other hand is incorporated via the nonlocal mechanism provided by the NOSBPD. For model validation, three benchmark problems were solved using the proposed framework. Results obtained were compared to results from analytical solution and solutions from referenced literature. In addition, parametric study was conducted to determine the influence of nonlocality on numerical prediction. Conclusions drawn from the validation studies presented are that the proposed framework is able to predict viscoelastic responses that agree well with local macro models as well as nonlocal micromodels/nanomodels as reported in the literature.

Symmetrical Solutions for Non-Local Fractional Integro-Differential Equations via Caputo–Katugampola Derivatives

Fractional calculus, which deals with the concept of fractional derivatives and integrals, has become an important area of research, due to its ability to capture memory effects and non-local behavior in the modeling of real-world phenomena. In this work, we study a new class of fractional Volterra–Fredholm integro-differential equations, involving the Caputo–Katugampola fractional derivative. By applying the Krasnoselskii and Banach fixed-point theorems, we prove the existence and uniqueness of solutions to this problem. The modified Adomian decomposition method is used, to solve the resulting fractional differential equations. This technique rapidly provides convergent successive approximations of the exact solution to the given problem; therefore, we investigate the convergence of approximate solutions, using the modified Adomian decomposition method. Finally, we provide an example, to demonstrate our results. Our findings contribute to the current understanding of fractional integro-differential equations and their solutions, and have the potential to inform future research in this area.

Ultrathin Acoustic Holography

AbstractHow to realize acoustic holography via ultradeep‐subwavelength structures is a challenging problem in the past decades, which is thought impossible due to the linear proportional relationship between the structural thickness and acoustic wavelength. In this article, the methodology of ultrathin holography by patterning holes in an acoustic insulation plate with an ultradeep‐subwavelength thickness is introduced. The transmitted sound field can be manipulated arbitrarily to form a desired shape by designing the ultrathin pattern based on the nonlocal wave interaction theory. The physical mechanism of the nonlocal behavior to achieve a sophisticated hologram is revealed due to the interaction among the sound wave components themselves. Furthermore, the experiments are designed to map out the pressure amplitude field of a “sun” pattern in air and water, respectively. The work demonstrates the advantage of nonlocal ultrathin holography in the applications of ultrathin acoustic devices and provides inspiration for the holographic wave manipulation.

The fractional evolution equations associated with the quantum fractional number operator

The Liouville–Caputo and Riemann–Liouville fractional derivatives have been two of the most useful operators for modeling nonlocal behaviors by fractional differential equations. In terms of Mittag–Leffler function and convolution product, using the Laplace transform, we give the exact values of the solutions of the Liouville–Caputo and Riemann–Liouville time fractional evolution equations associated with the Quantum fractional number operator. Therefore, we study the attractiveness of these solutions.

A renovated Jaffrey-Hamel flow problem and new scaling statistics for heat, mass fluxes with Cattaneo–Christov heat flux model

In dire situations, such as the restricted spatial scale in nanoparticle systems and the analogous analysis of non-Fourier heat conduction and conventional heat conduction, the transmission of heat and momentum will exhibit non-linear and nonlocal behavior. The mechanisms of heat and mass transfer for non-Newtonian fluid flow between two inclined planes (convergent channel) with porous walled are taken into consideration. The Jaffrey-Hamel flow equation is renovated with the contribution of Carreau rheological model. The Cattaneo heat flux is presented to designate the anomalous heat, mass transport of Carreau nanofluid considering the influences of radiation flux, Brownian diffusion, and thermophoresis. Assumption, theories, and conservation law's leads to governing PDEs, which are solved numerically by invoking the Keller-Box scheme. It was concluded that for both conduit, flow reversal occurs only in the divergent domain of the channel but not in the converging where rapid acceleration of flow occurs, and inertial forces dominate the transport process. The flow instability in a porous media incorporate fluid inertia. The renovated model, which incorporates non-Fourier's law of heat conduction, can explain the anomalous thermal conductivity enhancement. The thermal relaxation effects the heat flux significantly, the conduction mechanism switches to oscillatory conduction with narrower temperature.